Saint Eustratius came from the city of Tarsus. At twenty years of age he secretly left his parents' home and settled in the Abgar monastery (on Olympos in Asia Minor). There he lived a strict ascetic life, eating only bread and water, and spending his nights at prayer. After a certain while he was chosen as igumen of the monastery.
During the reign of the Iconoclast Leo the Armenian (813-820), St Eustratius hid from pursuit by roaming the hills and the wilds. After the death of the emperor he returned to the monastery. Prayer was always on his lips, and he constantly repeated the words: "Lord, have mercy!"
Before his death he gave instructions to the monks not to be attracted towards earthly blessings, and constantly to think about the future life. Signing himself with the Sign of the Cross, he said, "Into Thy hands, O Lord, I commend my spirit" and he died in peace at age 95.